Southwestern Deserts

May, 2009
Regional Report

Mulch Plants

Mulch around all plants to conserve moisture, reduce soil temperatures and inhibit weed seed germination. Layer several inches of any organic material such as compost, bark, straw or chipped matter. It's especially important around non-native, moisture-sensitive plants such as roses and hibiscus. Spread the mulch out past the plant's drip line but leave several inches of bare ground around the stem or trunk to prevent wet mulch from sitting against the plant tissue.

Increase Watering Frequency

Increase watering frequencies as summer temperatures heat up. Continue to apply the same total amount of water, but water more often. Water should penetrate about 1 foot deep for small annuals and perennials, 2 feet for larger shrubs and 3 feet for trees. To determine how far water has spread, poke a probe into the soil. Any long, pointed piece of metal or wood will work. It will move through moist soil but stop when it hits dry soil.

Remove Spent Cool-Season Annuals

Most cool-season annuals are reaching the end of the line. Let them continue going to seed, either to save it for yourself or let the birds enjoy it. Pull the spent plants and chop them up for the compost pile. Do not save seed from hybrids, as it will not mature identical to the parent plant.

Plant Sun-loving Flowers

Sow seeds for sunflowers, zinnias, tithonia, Mexican hat and coreopsis in improved garden soil. Keep consistently moist until germination. Gradually reduce watering frequency. As plants mature, water should reach through the entire root system, about 12 inches deep. Cut flowers frequently for bouquets and they will reward you with a long bloom season.

Fertilize Citrus

Supply citrus with their second "feeding" of their year, applying one-third of the tree's total annual nitrogen requirement. As a general guideline, a mature citrus that has been in the ground for 6 years needs about 1.5 pounds of actual nitrogen per year. Apply about one-half pound at each feeding. Water well immediately after applying to help prevent burn.